1,247 research outputs found
Multilevel Preconditioning of Discontinuous-Galerkin Spectral Element Methods, Part I: Geometrically Conforming Meshes
This paper is concerned with the design, analysis and implementation of
preconditioning concepts for spectral Discontinuous Galerkin discretizations of
elliptic boundary value problems. While presently known techniques realize a
growth of the condition numbers that is logarithmic in the polynomial degrees
when all degrees are equal and quadratic otherwise, our main objective is to
realize full robustness with respect to arbitrarily large locally varying
polynomial degrees degrees, i.e., under mild grading constraints condition
numbers stay uniformly bounded with respect to the mesh size and variable
degrees. The conceptual foundation of the envisaged preconditioners is the
auxiliary space method. The main conceptual ingredients that will be shown in
this framework to yield "optimal" preconditioners in the above sense are
Legendre-Gauss-Lobatto grids in connection with certain associated anisotropic
nested dyadic grids as well as specially adapted wavelet preconditioners for
the resulting low order auxiliary problems. Moreover, the preconditioners have
a modular form that facilitates somewhat simplified partial realizations. One
of the components can, for instance, be conveniently combined with domain
decomposition, at the expense though of a logarithmic growth of condition
numbers. Our analysis is complemented by quantitative experimental studies of
the main components.Comment: 41 pages, 11 figures; Major revision: rearrangement of the contents
for better readability, part on wavelet preconditioner adde
Degradation of C.I. Reactive Orange 4 and its simulated dyebath wastewater by heterogeneous photocatalysis
The commercial azo dye C.I. Reactive Orange 4 in its reactive and hydrolysed forms can be efficiently photodegraded, using commercial samples of TiO2 as a photocatalyst. With UV light, aqueous solutions containing only dye and no dyebath additives are decolorised slightly more rapidly with Riedel-de-Häen TiO2 than with Degussa P-25 TiO2 . The rate of decolorisation increases markedly with increasing pH. Sunlight is also very effective as a light source. On the other hand, comparison experiments involving UV irradiation of hydrolysed and unhydrolysed Reactive Orange 4 in a simulated spent dyebath showed Degussa P-25 TiO2 to be significantly the more efficient catalyst, giving more than 90% decolorisation after 20 minutes.PRAXIS XXI/2/2.1/44/94.
FEDER
Development of membranes with regions with different characteristics by phase inversion technique
Separation membrane cells comprising membrane sections with different characteristics can be thebase for new separation processes. Hybrid membrane cells require new membranes with regions withdifferent characteristics. In this paper we present numerical and experimental approaches to developsuch membranes by the phase inversion technique. The two main steps of the phase inversiontechnique, the evaporation step and the immersion precipitation step, are studied by numericalmethods. The numerical approach is based on the solution of the mass transport equation to predict thefilm composition after the evaporation step and in the solution of the CahnHilliard equations topredict the structure of the membrane after the immersion precipitation step. The equations are solvedby finite difference methods. The numerical simulations are used to predict the influence of severalexperimental parameters (temperature, composition of the initial polymeric solution, evaporation time,precipitation time, immersion bath composition) in the structure of the membrane. The experimentalapproach is based on the manipulation of the experimental conditions to produce regions of differentcharacteristics in the same membrane. An experimental method to create different regions from twodifferent initial polymeric solutions is presented
Flow around individual Taylor bubbles rising in stagnant CMC solutions: PIV measurements
The flow around single Taylor bubbles rising in non-Newtonian solutions of Carboxymethylcellulose (CMC) polymer was studiedusing a simultaneous technique employing particle image velocimetry (PIV) and shadowgraphy. This technique solved previousproblems on finding the correct position of the bubble interface. Solutions of different polymer weight percentage, varying from0.1 to 1.0 wt% were used to cover a wide range of flow regimes. The rheological fluid properties and pipe dimension yieldedReynolds numbers between 4 and 254 and Deborah numbers between 0.012 and 0.402. The shape of the bubbles in the differentfluids was compared. The flow around the nose of the bubbles was found to be similar in all the studied conditions. Velocityprofiles in the liquid film around the bubble were measured. Different wake structures were found in the different solutionsstudied. With increasing viscosity, the wake flow varied from turbulent to laminar, being possible to observe a negative wake forthe higher polymer concentration solutions. A comparison between the different wake structures was made
Psychometric study of the European Portuguese version of the PedsQL 3.0 Cancer Module
Background: Health-related quality of life (HRQoL) is an important outcome to assess the impact of cancer. This article examines the psychometric properties of the European Portuguese self-report version of the Pediatric Quality of Life InventoryTM Cancer Module (PedsQLTM 3.0 Cancer Module) in children and adolescents with cancer.
Methods: The participants, 332 children/adolescents diagnosed with cancer (8–18 years old), completed measures to assess HRQoL (PedsQLTM 3.0 Cancer Module and DISABKIDS Chronic Generic Measure; DCGM-12) and anxiety (Revised Children’s Manifest Anxiety Scale - second edition; RCMAS-2). A subsample (n = 52) completed the PedsQLTM 3.0 Cancer Module a second time following one-week. The pediatric oncologists completed the Intensity of Treatment Rating Scale 3.0 (ITR 3.0).
Results: For the whole sample, the PedsQLTM 3.0 Cancer Module demonstrated good item discrimination (rs = .30 to .54). The confirmatory factor analysis testing the presence of eight first-order factors loading significantly in a second-order factor revealed an acceptable fit (CFI = .91; RMSEA = .05). The correlation of PedsQLTM 3.0 Cancer Module with DCGM-12 (rs = .17 to .58), and with RCMAS-2 (rs = −.16 to–.51) attested convergent validity. This inventory demonstrated minimally acceptable to very good internal consistency (αs = .65 to .87) and temporal stability (ICCs = .61 to .81).
Conclusions: These findings demonstrate that the European Portuguese self-report version of the PedsQLTM 3.0 Cancer Module is a valid and reliable instrument for assessing HRQoL in pediatric cancer.
Keywords: European Portuguese version, PedsQLTM 3.0 Cancer Module, Health-related quality of life, Pediatric cancer, Psychometric propertie
Synthesis of esters derived from 2,3,4-tri-O-benzyl-alpha-D-methylglucoside
The synthesis of a set of esters obtained from the D-glucose derivative by reaction with several carboxylic acids: benzoic, phenylacetic, acetylsalicylic, 2-(3-bromopropoxy)benzoic acid and 4-(toluene-4-
sulfonylamino)benzoic acid.FCT (Fundação para a Ciência e Tecnologia) and FEDER for financial support. The Bruker Avance
III 400 spectrometer is part of the National NMR network and was purchased under the framework of the National Programme for Scientific Reequipment,
contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and (FCT). We are also grateful for research grant VZ MSMT-
0021627501, Czech Republic
LYTAG-driven purification strategies as a key to integrate and intensify the downstream processing of monoclonal antibodies
Monoclonal antibodies (mAbs) are currently the most important class of recombinant protein therapeutics in the biotechnological and biopharmaceutical industry with more than 250 mAbs currently undergoing clinical trials. High titer producing cultures and complex mixtures containing high cell densities, together with an increasing growing demand for highly pure mAbs is making recovery and purification processes hot targets for improvement and opens important technological challenges in mAbs manufacturing platforms.
This work explores the use of an affinity dual ligand based on a choline binding polypeptide tag (LYTAG) fused with the synthetic antibody Z domain (LYTAG-Z) as a tool to integrate and optimized the downstream processing of mAbs. Upon addition of this ligand to an animal cell culture broth, antibody-LYTAG-Z complexes are formed which can be easily captured and separated from host cell impurities by affinity partitioning in aqueous two-phase systems (ATPS) composed of polyethylene glycol –PEG, as PEG molecules have the ability to binding to the choline binding sites of LYTAG. Integration of clarification and primary mAbs recovery was successfully accomplished using a system composed of 6% PEG 3350 Da and 7% dextran 500,000 Da in which an extraction yield of 89% and a clarification higher than 95% were achieved. IgG-rich phases were further processed by chromatography, using three different strong anion exchange matrices charged with quaternary methyl amines (a choline analogue) – CIMmultus QA, HiTrap Q FF and gPore NW Q. A two-elution method was developed for the separation of the antibody-LYTAG-Z complexe, allowing simultaneous purification of the antibody and recovery of the ligand.
The process was successfully scale-up 10000 times allowing a global antibody recovery of 70% with a purity of 89% and enabling 100% cell removal
Analisador paramétrico de transístores com controlo de temperatura
Neste documento é descrito um analisador de características estáticas de transístores de junção bipolar cuja temperatura da cápsula do transístor em teste pode ser controlada, constituindo assim um dos parâmetros de análise.
O analisador foi desenvolvido para suprir a necessidade de demonstração em aulas laboratoriais da dependência com a temperatura de algumas características estáticas dos transístores bipolares, tendo portanto um cariz eminentemente pedagógico.info:eu-repo/semantics/publishedVersio
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